Chapter 5 Flashcards
Passive transport
movement of substances across a cell’s membrane without expenditure of energy
Diffusion
Net movement of substances from regions of high concentration to regions of lower concentration
Facilitated diffusion
diffusion of molecules or ions through carrier proteins or ion channels
Channel proteins
Carrier proteins
Membrane protein that binds to a molecule that cannot cross the membrane
Ion channels
Membrane proteins that allow passage of ions through phospholipid bilayer
Gated channels
Channel proteins that can be opened or closed in response to a stimulus
______ ________ is diffusion facilitated by membrane proteins.
Facilitated diffusion
Facilitated diffusion requires a ________ _______.
Concentration gradient
Aqueous solution
Water-based solution
Osmosis
Net diffusion of water across a membrane toward a higher solute concentration
Osmosis and diffusion are the same except osmosis involves _______.
Water
Concentration of all solutes in a solution determines the _______ ________.
Osmotic concentration
Hypertonic
Solution with higher concentration of solutes than the cell
Hypotonic
Solution with lower concentration of solutes than the cell
Isotonic
Solution having the same concentration of solutes as the fell
What happens to a cell in a hypotonic solution?
• Cytoplasm is hypertonic relative to extracellular fluid
• Water diffuses into cell —> cell swells
• Increases pressure of cytoplasm pushing on cell membrane